Casemate privacy =Proximity sensor issues?

I recently returned my iP4 because I got it swapped out a few times because of very bad proximity sensor issues. The whole time I had the privacy screen protector from casemate, sold at AT&T. So today my boy buys one and his iP4 has no issues. After he puts on the screen protector he starts having the same proximity sensor issues I had!! After he takes it off everything went back to normal......and what do I do now that I returned my iPhone because of the proximity issue?!?!......Screw that right then and there I asked if they had any in stock and ala Madden BOOM!...I got me another iP4....and no issues whatsoever!!!!

 

I'm going to order a set from power support and get a warranty replacement from zagg for the back.